The Effect of Transglutaminase Crosslinking on the Rheological Characteristics of Heated Peanut Flour Dispersions

Effects of myofibril-palatinose conjugate as a phosphate substitute on meat emulsion quality

The objective of this study was to investigate a replacement for phosphate in meat products. Protein structural modification was employed in this study, and grafted myofibrillar protein (MP) with palatinose was added to meat emulsion without phosphate. Here, 0.15% of sodium polyphosphate (SPP) was replaced by the same (0.15%) concentration and double (0.3%) the concentration of grafted MP. Although the thermal stability was decreased, the addition of transglutaminase could increase stability. The rheological properties and pH also increased with the addition of grafted MP and transglutaminase. The addition of grafted protein could be perceived by the naked eye by observing a color difference before cooking, but it was not easy to detect after cooking. The cooking loss, emulsion stability, water holding capacity, lipid oxidation, and textural properties improved with the addition of grafted MP. However, the excessive addition of grafted MP and transglutaminase was not recommended to produce a high quality of phosphate replaced meat emulsion, and 0.15% was identified as a suitable addition ratio of grafted MP.

Application of transglutaminase modifications for improving protein fibrous structures from different sources by high-moisture extruding

Plant proteins can be extruded under high moisture content (above 40 %) to form meat-like fibrous structures, which is the basis for meat-like substitute products. However, the proteins' extrudability from various sources remain challenging in terms of generating fibrous structures under combinations of high-moisture extrusion with transglutaminase (TGase) modifications. In this study, proteins from soy (soy protein isolate, SPI, and soy protein concentrate, SPC), pea (pea protein isolate, PPI), peanut (peanut protein powder, PPP), wheat (wheat gluten, WG), and rice (rice protein isolate, RPI) were texturized using high-moisture extrusion combined with transglutaminase (TGase) modifications to enact changes in protein structure and extrusion capabilities. The results showed that soy proteins (SPI or SPC) responsed to torque, die pressure and temperature during extrusion, and this phenomenon was more pronounced at a higher protein content (SPI). In contrast, rice protein exhibited poor extrudability, leading to large losses of thermomechanical energy. TGase significantly affects the orientation of protein fibrous structures along the extrusion direction by impacting the rate of protein gelation during the high-moisture extrusion process, with the impact mainly occurring in the cooling die. Globulins (mainly 11S) played a major role in forming fibrous structures and the aggregation of globulins or reduction of gliadins under TGase modification impacted the orientation of the fibrous structure along the extrusion direction. Some thermomechanical treatment during high-moisture extrusion results in protein conversion from compact structure into more extended or stretched state, and the increase of random coil structures for proteins derived from wheat and rice would lead to these looser structures in the extrudates. Thus, TGase can be combined with high-moisture extrusion to regulate the formation of plant protein fibrous structures, dependent on the specific protein source and content.

Effects of Disinfectants on Larval Growth and Gut Microbial Communities of Black Soldier Fly Larvae

The use of the black soldier fly has been demonstrated to be effective in the treatment of swine manure. Since the outbreaks of ASFV, prevention procedures, including manure disinfection, have changed dramatically. Glutaraldehyde (GA) and potassium peroxymonosulfate (PPMS) have been shown to be effective in the prevention of this pathogen and are thus widely used in the disinfection of swine manures, etc. However, research on the effects of disinfectants in manures on the growth of BSFL and gut microbiota is scarce. The goal of this study was to determine the effects of GA and PPMS on BSFL growth, manure reduction, and gut microbiota. In triplicate, 100 larvae were inoculated in 100 g of each type of manure compound (manure containing 1% GA treatment (GT1), manure containing 0.5% GA treatment (GT2), manure containing 1% PPMS treatment (PT1), manure containing 0.5% PPMS treatment (PT2), and manure without disinfectant (control)). After calculating the larval weight and waste reduction, the larval gut was extracted and used to determine the microbial composition. According to the results, the dry weights of the larvae fed PT1-2 (PT1: 86.7 ± 4.2 mg and PT2: 85.3 ± 1.3 mg) were significantly higher than those of the larvae fed GT1-2 (GT1: 72.5 ± 2.1 mg and GT2: 70 ± 2.8 mg) and the control (64.2 ± 5.8 mg). There was a 2.8-4.03% higher waste reduction in PT1-2 than in the control, and the waste reduction in GT1-2 was 7.17-7.87% lower than that in the control. In a gut microbiota analysis, two new genera (Fluviicola and Fusobacterium) were discovered in PT1-2 when compared to GT1-2 and the control. Furthermore, the disinfectants did not reduce the diversity of the microbial community; rather, Shannon indices revealed that the diversities of GT1-2 (GT1: 1.924 ± 0.015; GT2: 1.944 ± 0.016) and PT1 (1.861 ± 0.016) were higher than those of the control (1.738 ± 0.015). Finally, it was found that both disinfectants in swine manures at concentrations of 1% and 0.5% may be beneficial to the complexity and cooperation of BSFL gut microbiota, according to an analysis of microbial interactions.

Inorganic/Biopolymers Hybrid Hydrogels Dual Cross-Linked for Bone Tissue Regeneration

In tissue engineering, the potential of re-growing new tissue has been considered, however, developments towards such clinical and commercial outcomes have been modest. One of the most important elements here is the selection of a biomaterial that serves as a "scaffold" for the regeneration process. Herein, we designed hydrogels composed of two biocompatible natural polymers, namely gelatin with photopolymerizable functionalities and a pectin derivative amenable to direct protein conjugation. Aiming to design biomimetic hydrogels for bone regeneration, this study proposes double-reinforcement by way of inorganic/biopolymer hybrid filling composed of Si-based compounds and cellulose nanofibers. To attain networks with high flexibility and elastic modulus, a double-crosslinking strategy was envisioned-photochemical and enzyme-mediated conjugation reactions. The dual cross-linked procedure will generate intra- and intermolecular interactions between the protein and polysaccharide and might be a resourceful strategy to develop innovative scaffolding materials.

Combined effects of ionic strength and enzymatic pre-treatment in thermal gelation of peanut proteins extracts

Peanut proteins are mostly composed of arachins and conarachins, globular proteins that can form gels under thermal denaturation or enzymatic treatment. We explored here how ionic strength (0.5 M or 0.8 M) and gelation process (a thermal treatment preceded or not by an enzymatic pre-treatment) could affect peanut protein gel properties. Gel formation and final properties were characterized by rheology, and gel structure was observed by confocal microscopy. We found that the ionic strength imposed during protein extraction determines the arachins/conarachins ratio, and that conarachins-rich samples give stronger gels, which is attributed to their higher content in free thiol groups and lysine residues. The gel storage modulus exhibited a power-law dependence with the protein concentration, which exponent depended on the gelation process. Rheological results, together with confocal microscopy imaging, showed that an enzymatic pre-treatment resulted in denser structures than when a simple thermal treatment was applied.

Tissue transglutaminase: an emerging target for therapy and imaging

Tissue transglutaminase (transglutaminase 2) is a multifunctional enzyme with many interesting properties resulting in versatile roles in both physiology and pathophysiology. Herein, the particular involvement of the enzyme in human diseases will be outlined with special emphasis on its role in cancer and in tissue interactions with biomaterials. Despite recent progress in unraveling the different cellular functions of transglutaminase 2, several questions remain. Transglutaminase 2 features in both confirmed and some still ambiguous roles within pathological conditions, raising interest in developing inhibitors and imaging probes which target this enzyme. One important prerequisite for identifying and characterizing such molecular tools are reliable assay methods to measure the enzymatic activity. This digest Letter will provide clarification about the various assay methods described to date, accompanied by a discussion of recent progress in the development of inhibitors and imaging probes targeting transglutaminase 2.

Effects of transglutaminase catalysis on the functional and immunoglobulin binding properties of peanut flour dispersions containing casein

The functionality of light roasted peanut flour (PF) dispersions containing supplemental casein (CN) was altered after polymerization with microbial transglutaminase (TGase). The formation of high molecular weight covalent cross-links was observed with likely development of PF-PF, PF-CN, and CN-CN polymers based on Western blotting patterns visualized using antiserum directed against Ara h 1, Ara h 2, Ara h 3, or casein. The gelling temperature of TGase-treated PF dispersions containing 2.5% CN was significantly raised compared to the nontreated PF-CN control solutions. Furthermore, the gel strength and water holding capacity of cross-linked PF-CN test samples containing 5% CN was increased, while the yield stress and apparent viscosity were lowered compared to control dispersions. The immunological staining patterns were also changed where, in some cases, IgE binding to TGase-treated PF-CN fractions appeared less reactive compared to equivalent polymeric PF dispersions lacking supplemental CN and non-cross-linked PF-CN samples. Perhaps, covalent modification masked IgE peanut protein binding epitopes, at least to some degree, on an individual patient basis. Casein proved to be an effective cosubstrate with PF for creating Tgase modified PF-CN dispersions for use as a novel high protein food ingredient.